Now armed with a copy of King's words, the Diocese of Wilmington priest told us his heart was forever changed that day, August 28, 1963.

"So I come to say, 'Thanks,' and I come to read his speech and in my own way in my own heart to say, 'I'm doing my own part to try to keep your legacy alive,'" said Mast.

The 'Let Freedom Ring' celebration starts at 11:00 a.m. Wednesday and will last until 4:00 p.m.

President Barack Obama is due to speak just before 3:00 p.m. on the steps of the Lincoln Memorial. Former presidents Bill Clinton and Jimmy Carter are also scheduled to speak, as are Caroline Kennedy and Oprah Winfrey.